We used to jokingly tell our grown kids that they could not watch the PTL club. It was popular entertainment for college kids at that time. They seemed to find Tammy likable in spite of the mess that followed.
Her makeup was and has continued to be her trademark. Not only did others joke about it, so did she. I reckon she just wouldn't be her without the makeup.
I didn't watch the interview, but saw some promotions. I was shocked by her appearance. Yes, the mascara made it worse. But without it she would not have been Tammy. It probably gave her a lift to keep up her persona in the face of her impending death.
Angeline
Speakeasy Moderator
has Cancer, looks terrible, (65 lbs)
I don't think she would look quite as bad if she didn't use so much mascara, none would be better.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic